Contrary to what you’ll see in most action movies, bullets don’t actually travel through water very effectively at all. When a round impacts the water, it very literally impacts, often breaking apart or tumbling off of its trajectory because of the water’s density.

As we’ve covered here at SOFREP before, it doesn’t take much water to render most rounds inert — making it possible for Norwegian physicist Andreas Wahl to stand right in front of a submerged SIG SG 550 in a pool and use a rope to pull the trigger without fearing for his life.

For most folks, a weapon’s ability to take a life through the water isn’t a pressing concern; but for some very specific groups of war fighters, this presents a serious issue. Navy SEALs are known for conducting clandestine operations in and around the water, and Navy Frogmen are often tasked with preventing the foreign equivalent of our SEALs from doing the same near American shores. Because of this, specialized weapons have been developed over the years to allow them to do just that, like the Heckler & Koch P11 that saw heavy use during the Cold War — and likely still has a place in a few armories today.

The P11 fired 4″ steel darts with a range of between 30 and 50 feet under water, depending on depth. (WikiMedia Commons)

These highly specialized and rare weapons might do the job, but they aren’t all that practical. That’s why SOCOM is now looking into new rounds that can be fired from traditional weapons and penetrate the water without breaking apart or tumbling off course — making it possible to dramatically increase the capabilities of those tasked with sea-based combat operations. With rounds that can travel effectively through the water, SEALs could engage enemies from submerged positions, helicopter gunners could strafe submarines traveling at periscope depths, and American troops would have the distinct advantage in underwater engagements.

DSG Technologies has developed a tungsten-tipped round dubbed the CAV-X that creates a small air bubble around its tip as it travels through the air, significantly reducing the drag the round experiences in flight. In water, this bubble greatly reduces friction, allowing the round to travel in on a straight trajectory at high velocities thanks to a process called supercavitation.

The bullet (black) encounters a liquid (blue) at high speed. The fluid pressure behind the bullet is lowered below the vapor pressure of the liquid, forming a bubble of vapor (a cavity) that encompasses the bullet. This is called supercavitation. (WikiMedia Commons)

SOCOM is currently testing this round to see if it can provide a benefit to its personnel. While we don’t know what discussions are going on behind the closed doors of Special Operations Command, DSG did offer up a demonstration of their round last week. In the video below, you can watch a Colt AR-15 fire a CAV-X round through a whopping 13 blocks of ballistic gel — a material denser than water that’s often used to approximate human tissue. A normal round will only penetrate a block or two.